1. Field of the Invention
The present invention relates to Raman spectroscopy probes and, more particularly, to a probe which can withstand elevated temperatures.
2. Related Art
In many applications, laser beams are used to excite materials so that the Raman spectra can be analyzed. A measurement device including an axial pass-through Raman cell is disclosed in U.S. Pat. No. 5,194,913, to Myrick et al., the disclosure of which is hereby incorporated by reference. The measurement device uses an optical fiber for delivering the laser light to the sample, which requires the use of a bandpass filter. The sending and receiving optical fibers must be aligned on opposite sides of the sample with a predetermined distance between them. As a consequence, this device can only be used in one location.
Present Raman spectroscopy systems suffer from a number of shortcomings. For example, some operate best on liquids and gases, but not solids. Others are fixed and cannot be used in more than one location. In addition, prior art Raman spectroscopy probes cannot withstand hostile environments such as elevated temperatures, i.e., temperatures as high as 550.degree. F. and elevated pressures, i.e., pressures as high as 2500 psig. Therefore, there exists a need in the art for a Raman spectroscopy probe which can be used in more than one location, can effectively operate on liquids, gases and solids, and can withstand hostile environments such as high temperatures and high pressures.